The 89-year-old, whose career as a racing commentator began in 1948, has a mild form of lymphoma.

The cancer was found during tests in hospital after he fell while on a German river cruise last month.

Walker is due to start chemotherapy on June 29 – the eve of the British Grand Prix – and has pledged to beat cancer.

He said: "They've caught it incredibly early. It's treatable, the doctors say my condition is mild and I'm very hopeful."

Murray had broken his pelvis and spent three weeks in hospital before returning to his Hampshire home but had vowed to return to be well enough for the Grand Prix.

Sources close to the popular broadcaster say he is in “good spirits”. BBC Radio Five Live F1 presenter Maurice Hamilton posted on Twitter: “Thoughts go out to Murray Walker, blood tests during recovery from fall injury showing he has cancer – which is treatable.

“Despite having to face chemo, Murray is more concerned about having to miss Silverstone and Goodwood. Typical.”